This a partial patch -- you're expected to hand-munge the code
after understanding what it does..

..and to save everyone a lot of bother, the font header files & etc.
have been provided in utils_dir.tar

--
Chris Baird,, <chris.j.baird@gmail.com> June 2024.


diff -U5 -t --suppress-blank-empty -r -N -E -Z -b -w -B uv-k5-firmware-custom/font.c /home/cjb/uvk2cjb/font.c
--- uv-k5-firmware-custom/font.c	2024-06-23 14:06:24.269187381 +1000
+++ /home/cjb/uvk2cjb/font.c	2024-05-20 15:56:24.399199875 +1000
@@ -14,19 +14,36 @@

 #include "font.h"

         const uint8_t gFontBigDigits[11][26 - 6] =
         {
+    {0xFC, 0xFE, 0xFE, 0x06, 0x86, 0xC6, 0xE6, 0xFE, 0xFE, 0xFC, 0x3F, 0x7F, 0x7F, 0x67, 0x63, 0x61, 0x60, 0x7F, 0x7F, 0x3F, },
+    {0x00, 0x00, 0x18, 0x1C, 0xFE, 0xFE, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0x60, 0x7F, 0x7F, 0x7F, 0x60, 0x60, 0x00, },
+    {0x1C, 0x1E, 0x1E, 0x06, 0x06, 0x06, 0x86, 0xFE, 0xFE, 0x7C, 0x60, 0x70, 0x78, 0x7C, 0x6E, 0x67, 0x63, 0x61, 0x60, 0x60, },
+    {0x0C, 0x0E, 0x0E, 0x86, 0x86, 0x86, 0x86, 0xFE, 0xFE, 0x7C, 0x30, 0x70, 0x70, 0x61, 0x61, 0x61, 0x61, 0x7F, 0x7F, 0x3E, },
+    {0x80, 0xC0, 0xE0, 0x70, 0x38, 0x1C, 0x0E, 0xFE, 0xFE, 0xFE, 0x0F, 0x0F, 0x0F, 0x0C, 0x0C, 0x0C, 0x0C, 0x7F, 0x7F, 0x7F, },
+    {0xFE, 0xFE, 0xFE, 0xC6, 0xC6, 0xC6, 0xC6, 0xC6, 0xC6, 0x86, 0x30, 0x70, 0x70, 0x60, 0x60, 0x60, 0x60, 0x7F, 0x7F, 0x3F, },
+    {0xF8, 0xFC, 0xFE, 0xC6, 0xC6, 0xC6, 0xC6, 0xC6, 0xC6, 0x80, 0x3F, 0x7F, 0x7F, 0x60, 0x60, 0x60, 0x60, 0x7F, 0x7F, 0x3F, },
+    {0x0E, 0x0E, 0x0E, 0x06, 0x06, 0x86, 0xE6, 0xFE, 0x7E, 0x1E, 0x00, 0x00, 0x00, 0x00, 0x7C, 0x7F, 0x7F, 0x03, 0x00, 0x00, },
+    {0x7C, 0xFE, 0xFE, 0x86, 0x86, 0x86, 0x86, 0xFE, 0xFE, 0x7C, 0x3F, 0x7F, 0x7F, 0x61, 0x61, 0x61, 0x61, 0x7F, 0x7F, 0x3F, },
+    {0xFC, 0xFE, 0xFE, 0x06, 0x06, 0x06, 0x06, 0xFE, 0xFE, 0xFC, 0x01, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x7F, 0x3F, 0x1F, },
+    {0x00, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, }
         };
 #endif

+const uint8_t gFontBig[95 - 1][16 - 2] =
 {
+#include <utils/c64large.h>
 };
+
+
 const uint8_t gFontSmall[95-1][6] =
 {
+#include <utils/c64font.h>  //#include <utils/apple2.h>
 };

 #ifdef ENABLE_SMALL_BOLD
         const uint8_t gFontSmallBold[95 - 1][6] =
         {
+#include <utils/apple2.h>   //#include <utils/vicfont.h>
         };
 #endif


diff -U5 -t --suppress-blank-empty -r -N -E -Z -b -w -B uv-k5-firmware-custom/ui/helper.c /home/cjb/uvk2cjb/ui/helper.c
--- uv-k5-firmware-custom/ui/helper.c	2024-06-23 14:06:24.297187760 +1000
+++ /home/cjb/uvk2cjb/ui/helper.c	2024-05-19 15:43:31.872976896 +1000
@@ -143,18 +153,44 @@

 void UI_DisplayFrequency(const char *string, uint8_t X, uint8_t Y, bool center)
 {
+  const unsigned int char_width  = 8;
         uint8_t           *pFb0        = gFrameBuffer[Y] + X;
         uint8_t           *pFb1        = pFb0 + 128;
         bool               bCanDisplay = false;

         uint8_t len = strlen(string);

+  for (int i = 0; i < len; i++)
+    {
                 char c = string[i];
+
+      //if (c == '-')
+      //  c = '9' + 1;
+
                 if (bCanDisplay || c != ' ')
                 {
                         bCanDisplay = true;
+          if (c>='0' /*& c<='9' + 1*/)
+            {
+              for (int k = 0; k < 7; k++)
+                {
+                  *(pFb0 + 2 + k) = gFontBig[c-'!'][k];
+                  *(pFb0 + 3 + k) = gFontBig[c-'!'][k];
+                  *(pFb0 + 4 + k) = gFontBig[c-'!'][k];
+                  *(pFb1 + 2 + k) = gFontBig[c-'!'][k+7];
+                  *(pFb1 + 3 + k) = gFontBig[c-'!'][k+7];
+                  *(pFb1 + 4 + k) = gFontBig[c-'!'][k+7];
+                  pFb0 += 2;
+                  pFb1 += 2;
                         }
+            }
+          else
+            if(c == '.')
+              {
+                pFb0 += 2;
+                pFb1 += 2;
                                 *pFb1 = 0x60; pFb0++; pFb1++;
                                 *pFb1 = 0x60; pFb0++; pFb1++;
+                *pFb1 = 0x60;
                                 continue;
                         }

                 }
+      else
+        if (center)
+          {
                         pFb0 -= 6;
                         pFb1 -= 6;
                 }
                 pFb0 += char_width;
                 pFb1 += char_width;


